Note: Descriptions are shown in the official language in which they were submitted.
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Polyester compositions including fibers formed
therefrom, such as those obtained fro~ the products in U. S.
Patents 2,465,319 and 3,047,539 are readily flammable and have
the disadvantages that they tend to drlp while burning or
being sub~ect to flames and it is difficult to prevent the
dripping. Common flame retardant additives, such as phosphorus;
compounds and antimony compounds do not appear to be very
effective when used with polyesters. Polyesters are also
sub~ect to serious degradation in the presence of a number of
conventionally used flame retardants with a loss in physical
properties.
It has been known that flameproof fibers and filaments
can be made from various polymeric film-forming materials.
Generally, fibers made from such materials are quite expensive
and unsuitable for many uses. Such fibers have been blended
with filaments or fibers of a flammable nature in an attempt
to obtain textile products having non-flammable properties.
The fibrous products obtained from such a mixture of polyester
fibers still have deficiences making them unsuitable for many
uses if the proportion of non-flammable fibrous content is
high enoughto make the products self-extinguishing. For
example, non-flammable blends of a fiber formed of a halogen
containing polymer with a polyester type of fiber generally
contain from about 50 to about 65% by weight of the former
type of fiber (unless the blend also contains a large amount
of inorganic non-combustible materials) and textile products
made therefrom are deficient in cert~in properties. In woven
and non-woven textlles, the hand is frequently deficient.
Also, the use of conventional polymeric binders for sizing a
3o woven fabric or for bonding the fibers of a non-woven web
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tends to increase the flammability of the textile products.
In the production of bulky fibrous masses especially fiberfill
which is used in apparel, for example, linings for suits,
padded garments, such as bedjackets and smoking jackets, in-
sulated garments, such as sports jackets, bedding, such as
quilts, for upholstery padding and cushion fillers, including
automotive protective padding, such as "head-liners" in the
; ceiling or on the dashboards or steering wheels, the relatively
large proportion of halogen containing polymer imparts a
severe loss of resiliency and resulting tendency to pack down
in use.
In accordance ~ith the present invention from about
5 to 35% of a non-flammable halogen containing fib~r is
blended with from about 95 to ab~ut 65% of a polyester fiber
to afford products which when subaected to extreme heat will
not melt or b~rn. The products are used to prepare wcven
fabric or non-woven webs, batts or mat of fibers employed in
apparel as a textile fabric or as a liner or padding material,
as a stuffing material for upholstering purposes and the like.
In making a woven textile, a polymeric sizing material is
employed and comprises from about 5 to 20% by weight based
on the weight of fibers. This sizing is a polymer composition
which even when normally dried or cured or b~th on the textile
material to form part of the finished textile product, does
not support combustion. Similarly, in making a bulky non-woven
material for use as an upholstery stuffing, filler for
cushions or a n~n-woven textile suitable for use as a fabric,
such as a curtain, drapery and the like or as a lamina of a
multi-ply textile for use in garments, for example, shirt
3o collars, cuffs or linings for mens' suits from about 5 to
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about 50% by weight of a polymer binder composition based on
fiber weight which when dried and cured does not support com-
bustion, is used as a binder for bonding the fibers together.
~ One preferred embodiment of the present invention
is concerned with fibrous products comprising a major pro-
portion of polyester fibers obtained from terephthalates such
as those prepared from terephthalic acid and ethylene glycol,
dimethyl terephthalate and ethylene glycol, dimethyl tere-
phthalate and 1,4-cyclohexanedimethanol and the like. Trade-
marks of various products prepared from terephthalate include
Dacron, Terylene, Kodel, Diolen, ~nkalene, Fortrel, Tergal,
Terital, Terlenka, Trevira and the like which are of the
thermoplastic character. These fibers are blended with from
about 5 to about 35% by weight based on the total weight of
the fiber blend, of a halogen containing polymer, such as homo-
polymers and copolymers of vinyl chloride, vinylidene chloride,
vinyl fluoride, vinylidene bromide, tetrafluoroethylene and
the like. Preferably, the fiber blend comprises a mixture of
from about 5 to about 35% by weight of halogen containing
thermoplastic fibers and from about 65 to about ~5~ by weight
of thermoplastic polyester fibers. Non-woven fabrics are made
from these blends by bonding the fibers distributed in random
array with a polymer composition which contains a substantial
amount of halogen, preferably chlorine, in the prepolymer.
It has been found that by employing non-flam~able
fibers, in the range of from about 5 to about 50% and prefer-
ably in the range of from about 5 to about 35%, which contain
from about 10 to about 60~ by weight of a halogen such as
chlorine and bromine and having a shrinkage temperature of at
3o least 250F. and preferably above 300F., in the blend with
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the polyester fibers, together wit~ a sizing or binding polymer
composition containing from about 60 toabout go~by weight of
vinylidene chloride prevents dripping of melted fiber on
exposure of the fiber mass to an open flame. Vinyl chloride,
vinyl bromide, vinylidene chloride or vinylidene bromide
homopolymers and copolymers as well as vinyl chloride contain-
ing modacrylic fibers and vinylidene chloride containing moda-
crylic fibers such as those disclosed in U. S. 3,516,903
may be used in the fiber blend.
The chlorine containing polymer fiber which is blended
with the polyester must be of the type that will not shrivel
into a knotty mass nor shrink more than about 15% lengthwise
(measured on the length of the individual fiber) when subjected
, to the drying and curing temperatures employed on a sized woven
fabric or a fiber-bonded non-woven product. These products are
used as textile fabrics or as stuffing in upholstery. Pre-
ferred polymers include syndiotactic polyvinyl chlorides such
as one sold under the trademark Leavil; vinyl chloride polymer
fibers which heat-set above 300F., for example, a copolymer
containing about 50~ vinyl chloride and about 50% vinyl alcohol
sold under the trademark Cordelan; modacrylic fibers formed
from copolymers containing from about 35 to about 85% by
weight of acrylonitrile, 15 to 65% of vinyl chloride or vinyl-
idene chloride and up to about 10% of other comonomers, such
as vinyl acetate, ~-vinylpyridine, methyl acrylate, ethyl
acrylate and the like. A preferred modacrylic fiber is
Verel which contains about 50% acrylonitrile and about 50%
vinyl chloride. U. S. Patent No. 3,516,903 discloses other
modacrylic ,fibers which may be used,
* Trademark
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~ile adequate non-flammability may be obtained by
blendlng a polyester and halogen containlng fiber ln the
proportions speciried ab~e~ it is often useful to add one or
more flame retardants. By addlng such retardants the ratio
between the polyester fibers and the halogen containing fibers
may be lncreased without loss of non-flammability so that
additional variations in properties such as wash durability,
durability to dry cleaning, resiliency and desired color may
be attained. The coating or b~nding copolymers employed in
this invention are themselves flame retardants. When an
additional flame retardant is employed, such as one or more
of those described below, it has b3en found that there is a
synergistic effect in flame retardancy. This synergistic i
effect is not wlth only some of the flame retardants meniioned 4
below, but with all of them.
T~e more important of the flame retardant synergists
contain halogen such as bromine or chlorine, antimony, phosphor-
us or nitrogen. These various synergists and the oxides of
various metals including the oxid~ of antimony, arsenic,
aluminum, boron and zinc may be used. Antimony oxide is
especially useful for this purpose. The flame retardant
additive may also be a halogenated organic compound; a
boron containing compound such as zinc borate and the like;
a mixture of a halogen organic compound and one of the metal
oxides, or a phosphorus- co~pound such as zinc phosphate; a
mixture of a halogenated compound with a phosphorus compound
or compounds containlng phosphorus -~itrogen bonds or a
.
mixture of two or more of the foregoing.
The amount of flame retardant will naturally vary
with the nature of the fiber blend and with the efficicncy of
the addit1ve. Tne amount of additive may be up to about 10
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parts by weight per h mdred parts of fib~r. A preferred
amount will be in the range of from about 3 to about 7 parts
by weight of additive per 100 parts of fiber. ;s
Among the useful halogen containing compounds that
can be used as flame retardants are those described in U. S.
Patent No. 3,671,487, column 4, line 6, to column 5, line 68 F
inclusive.
~ Additional non-flammability in the properties of
the products can be obtained by introducing flame retardant
plasticizers, such as organic phosphate esters,phosphonate
esters and the like including tris-(2,3-dibro~opropyl)phos-
phate, tributyl phosphate, triphenyl phosphate, tricresyl
phosphate, tris(chloroethyl)phosphate and the like. The
plasticizers may be employed up to about 10~ by weight, based ;
on the weight of blended fibers. Examples of phosphonates
which can be employed appear in U. S. Serial No. 139,949,
filed May 3, 197~
The fibrous articles of the present invention do not
require appreciable amounts of inorganic fillers to ensure
that the article is self-extinguishing or that dripping of
polymer melt does not occur when the articles are subjected
to extreme heat.
The fibers may be blended by equipment commonly
used for this purpose, such as by an air-opener by which
25 - small b~tches of theseveral different fiber types are
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introduced in the propGrtions desired and blown into a chamber
by airjets. Other devices that can be employed to form a lap or
web of the blended fibers include pickers, cards, garnetts,
and Rando-Webber machines. ~he fibers produced by such equip-
ment are referred to as'~andomly distributedl' even though there
may be some orientation, especially in the carded web. The
length of the fibers or filaments may be from about 3/~ inch
to about 4 inches. In apparels, the preferred length is from
about i_l/2" to 2". In some instances, such as in making
stuffing materials for upholstering purposes, the length of
fiber may be from about 2 to about 10 inches, even up to
indefinite lengths (i.e., continuous filaments). Preferably,
the length is in the range of from about 1-1/2'` to about 2" S
plus or minus l/2 inch.
From the above described equipment, a web or fleece,
mat or batt may be taken and then converted into yarn on a
doubler or twister in conventional fashion which yarn can then
be woven into a fabric. Alternatively, the product obtained '~
from a card, garnett or "Rando-Webber" may be used in making a
non-woven web or la~ina, which may be assembled with itself
or other laminae, for example, other woven or non-woven materials.
These composite laminar fabrics are useful in making curtains,
draperies and upholstery stuffing.
Depending on the particular nature of final produc-t
desired, the denier of fibers used in the blends are in the
range of from about 0.5 to about 20. For use in making
upholstery stuffing a denier in the range of from about 5 to
about 18 is preferred. Smaller deniers in the range of from
about 2 to 5 are preferred for making bonded fiberfill or non-
wovens for use in apparel fabrics, curtains, draperies and the
like. ~or special uses, it is often desirable to use a blend
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of fibers of relatively small denier such as in the range of
from 2 to 5, with larger denier fibers, such as those in the
range of from 8 to 18.
The coating composition that is applied for bonding
fibers in the product comprises a copolymer of vinyl chloride,
vinylidenP chloride or a mixture thereof with halogen-free
comonomers. The proportion of chlorine containing monomers
in the copolymer is in the range of from ab~ut 60 to 90% by
weight. The copolymer also contains from about 1/2 to 5% by
weight based on the total weight of copolymer, of a reactive
co~onomer material, including N-me~hylolacrylamide, N-methylol-
methacrylamide, N-methylol-4-pentenoguanamine and the like.
The copolymers may also contain up to about 5~ by weight of
other comonomers which have a reactive hydrogen but are not
self-reactive, including monoethylenically unsaturatsd acids,
such as acrylic acid, methacrylic acid, itaco~ic acid and the
- like, amides of such acids, such as acrylamide, methacrylamide
and the like, hydroxy containing esters of such acids, such
- as ~-hydroxyethyl acrylate and ~-hydroxyethyl methacrylate, ~-
hydroxypropyl methacrylate, ~-hydroxypropyl acrylate, ~-
hydroxypropyl acrylate, a-hydroxypropyl methacrylate and the
like, aminoalkyl esters of such acids, such as N-dimethylamino-
ethyl acrylate, N-dimethylaminoethyl methacrylate, and
mixtures of two or more of the reactive monomers.
The copolymer ma-y also contain from about 9.5 to
about 40% by weight of relatively non-reactive monomers, such
as alkyl acrylates or methacrylates in which the alkyl has
from about 1 to ab~ut 18 carbon atoms and is preferably lower
alkyl of from 1 to 8 carbon atoms inc]uding methyl, ethyl,
n-butyl, hexyl, 2-ethylhexyl, lauryl, stearyl and the like
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with ethyl ac~ylate preferred, also other monomers such as
vinyl acetate, styrene, acrylonitrile or a mixture of such
monomers may be employed.
These copolymers may be applied as a solution or a
non-aqueous dispersion in a volatile organic solvent, such
as xylene, toluene, benzene, ethylene chloride, acetone,
dioxane, or mixtures thereof, at a polymer concentration of
from about 1 to about 30% by weight. Preferably, the co-
polymers are applied as aqueous dispersions of water insoluble
polymers obtained by emulsion copolymerization of the monomers
having a solids concentration in the range of from about 20 to
65% as initially prepared.
Application of the coating composition to the fibrous
product for sizing or for bonding fibers may be made by spraying
the solution or dispersion onto the fibrous product or by
immersing the fibrous product into the solution or dispersion
at concentrations having a sufficient wet pick-up ratio to
provide the desired proportion of polymer on the fibrous product.
The product is dried at a temperature in the range of from
about 140 to ab~ut 200F. and then cured by heating at a
temperature in the range of from about 250 to ab~ut 310F. for
from about 1 to about 5 minutes. When thicker products are
desired, application by spraying may involve spraying one side
of the product, drying it, and then spraying and drying the
other side, followed by curing at a temparature and for a time
in the range mentioned above.
In general, the relative proportions of the
polyester fiber, the halogen containing polymer fiber and the
binder copolymer specified above provide a wide range of bonded
3o fibrous products that are flame resistant, flame retardant,
or self-extinguishing. However, it is difficult to specify
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the overall rallges or proportions that will produce a bonded
fibrous product that is sufficiently flame-resistant for all
purposes in every instance. It is to be understood that the
selection of the relative proportions of the polyester and fi-
bers of halogen containing polymer may require (1) the bin~er
polymer to be employed in the lower part of the broad range 5
mentioned above or (2) that the binder polymer contain a pro-
portion of halogen containing monomer that is in the upper ~`~
part of the range specified. Many factors affect the flame
retardance in the fibrous blend, such as size (denier),
presence of colorant or delustrant, nature of crimpness,
porosity as well as the particular chemical composition of
the two fibers. The composition of and relative proportions
; between the fibers blended and the binder polymer should be
correlated to provide the flame resistant characteristics
desired in the final bonded product. This normally requires
only a simple experiment to check the combination selected.
TEST METHOD
The bonded web sample of about 1/2 to 3/4 inch
thickness and having the dimensions of 10 inches by 12 inches
is suspended vertically in air having normal room temperature
and humidity, for example, 25C. and 20 to 90% relative
humidity. A propane gas flame having a length of about
1-1/2 inches is directed into the surface of the hanging
web. The web is held in the flame for 5 seconds. This may
be done in a protective enclosure, such as a laboratory
hood. The extent of charring, melting, dripping and the
time of continued burning after removal of the flame is
recorded.
~rability of the sample to washing and dry cleaning
is tested by comparing (1) the results obtained on sample
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swatches of the bonded fibrous articles before any washing
or dry-cleaning and (2) the results obtained after subiecting
additional swatches of the same bonded article to one or
more washing or to one or more dry-cleaning operations or
to both washing and dry-cleaning.
For washing, a sample of the bonded web is introduced
into the washing machine in individually bagged, 80 sq.
bleached cotton sheeting with enough webs or enough terry
cloth toweling ballast to provide an 8 pound load in an
automatic home washer. The total wash cycle is about 34
minutes including the rinses and spin drying and the solution
used in the wash cycle is 15 gallons of water containing 1/2
cup of the commercially available detergent sold under the
trademark "Tide" at 140F. The total wash cycle is 15 minutes
f washing, 5minutesof spray-spin rinse, a deep rinse at 104F.
for about 2-1/2 minutes and about 3-1/2 minutes dry-spin. The
laundering is followed by tumble-drying in a home dryer at
the hot setting (about 120 to 140F.). The drying usually
takes about 20 minutes.
For dry-cleaning, the sample is placed in a bag.
The bag with its contents is placed into a laboratory model
of a dry-cleaning machine containing one gallon of perchloro-
ethylene. The bagged sample is tumbled for about 30 minutes.
- The bag is removed and the sample web is dried in a tumble dryer
at 120-140F.
The following examples are illustrative of the
invention, the parts and percentages given are by weight
and the temperature is Fahrenheit unless otherwise stated.
,
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1049205 ~
EXAMPLE 1
A fiberfill blend (garnet) is prepared containing
thoroughly distributed in random array, a mixture of 4
parts of 5-denier polyethylene terephthalates (Dacron 88)
ranging from about 2" to 2-1/2" long and 1 part of 5-denier
fibers of vinyl chloride polymer (Leavil) ranging fromabout
1-1/2'~ to about 2l' in length. A 3/4" thick, 10" x 12" sample
of this fiber blend (weighing 13.0 grams) is sprayed on one side
with a 23% solids dispersion of an emulsion copolymer of 85%
vinylidene chloride, 9.5% methyl acrylate, 3.5~ ethyl acrylate
and 2% of an approximately equimolar mixture of acrylamide and
N-methylolacrylamide. The sample is dried in aforced-air oven
at 240 to 260F. for about 2 minutes. The other side is
similarly sprayed with the same polymer dispersion, dried
as before (about 2 minutes at 240 to 260F.), and then cured
for 2 minutes at 300F. The cured sample weighs 15.1 grams
so the amount of the vinylidene chloride binder copolymer there-
in is approximately 16.1%, based on the fiber weight before
bonding. ~nen flame-tested in the manner described above with
3/4" of the flame extending into the sample, there is no
drip or melt even during exposure to the flame. Char length
is about 2" and burning ceases on removal of the flame.
EXAMPLE 2
By following substantially the procedure of Example 1
and by changing the ratio between the polyester fibers and
the polyvinyl chloride fibers from ~:1 to 2:1 and by
substituting for the copolymer of Example 1 an emulsion co-
polymer of 65% vinylidene chloride, 30% ethyl acrylate, and 4
acrylamide and N-methylolacrylamide in approximately equimolar
ratio, there is obtained a non-flam~able fabric. The add-on
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of the binder, determined after drying and curing is 16~. On
flame testing, no melt or drip-blrning occurs, the maximum
char length is 3-1/2" and on removal of the flame, the
burning either ceases immediately or within 7 seconds of the
removal of the flame.
EXAMPLE ~
By following substantially the procedure described
in Example 1 and by substituting for the fiberfill blend
described therein a 1:1 blend of polyalkylene terephthalate
fibers (Dacron 88) and 5-denier, 2" long methacryIic fibers
of a copolymer of 50~ vinylidene chloride and 50~ acrylonitrile
(Verel) there is obtained a fiber blend with a 27.5% add on after
spraying the binder of Example 1 which product when exposed to
flame in th~ manner described above neither melts nor drips.
EXAMPLE 4
By employing the blended fiber web prepared in the
manner as described in Example 3 and by employing as the
- b~nding copolymer the copolymer described in Example 2, there
~s obtained a flame resistant fiberfill blend having a 30%
add on which product when flame tested in the manner described
above neit-her ignltes nor melts or drips.
Tne following table illustrates other blends at
various ratios which have been treated with the binder dis-
clased in Examples 1 or 2 and which also may have been further
treated with colloidal antimony oxide at the 3.0% or 6.3%
level. The results clearly indicate the non-flam~ability of
the polyester blends both at the stage of original preparation
and also after washing and drycleaning.
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